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ELECTRICAL SIGNALING APPARATUS. No. 5445567. *Patented Aug'. 13, 1895.l

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W. W. DEAN. ELECTRICAL SIGNALING APPARATUS.

Patented Aug. 13, 1895.,

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BLBGTRIGAL SIGNALING APPARATUS.

Patented Aug. 13, 1895.

Unitime States' ldarssrr Ormea.

WILLIAM W. DEAN, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THE BELL TELE- PHONE COMPANY OF MISSOURI, OF SAME PLACE.

ELECTRIQAL SIGNALING APPARATUS.

SPECIFCATIN forming part of Letters Patent No. 544,567, dated August 13, 1895.

.To @ZZ whom it may concern,.-

Be it known that 1, WILLIAM W. DEAN, a 4citizen of the United States, residing at the city of St. Louis, in the State of Missouri,

have invented certain new and useful Improvements in Electrical Signaling Apparatus, more particularly for telephone systems, of which the following is such a full, clear, and exact description as will enable any one ro skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specification.

The invention consists in a new and useful I5 electromagnetic signaling apparatus, comprising preferably a plurality of electromagnets operating a signaling device; with an interlocking means whereby1 the magnets may separately or conjointly control the signals.

zo The invention also consists in the application of such a signaling apparatus to a telephone system, more particularly to a telephone system known as the common-battery system, patented on the 3d day of May,

1892,'to H. V. Hays, No. 474,323.

The invention also consists in a means for automatically signaling or calling or ringing up the subscriber wanted, which means may or may not be operatedby the signal appara- 3o tus referred to.

The invention also consists in certain combinations and features, which will be hereinafterset forth in full, and then pointed out in the claims making a part of this specification.

The invention will be best understood by referring to the accompanying drawings, in.

which the views on Sheet l illustrate the invention applied to a system of signaling generally and without having particular reference to a telephone system. The views upon the other sheets of the drawings illustrato the invention applied to a telephone-signaling system known as the common-battery system,patented as aforesaid.

Figures l and l:1 represent diagrammatically a plan and sectional side view, respectively, of my signaling apparatus. Fig. 2 is a perspective view of one of the magnet-armatures 5o and signaling-plate secured thereto.

and 3 are also plan and sectional side views,

Figs. 3.

Application tiled September 24, 1894. Serial No. 523,967. (No model.)

respectively, representing diagrammatically the signaling apparatus and showing some of the parts in different positions and giving another or second signal other than that indicated when the .parts are in their normal positions. Fig. 4 is a perspective view of the interlocking armature-lever bearing a signaling-plate. Figs. 5 and 5a are plan and sectional side views, respectively, representing 6o diagrammatically my signaling apparatus and showing the parts in still another position and giving still another or third signal. Figs. G and 6a are similar views showing some of the parts in still different positions and giving still another or fourth signal. Figs.7 and 7a are similar views showing the parts in different positions and giving a fifth signal. Fig. 8 is a top plan view illustrating the apparatus, the magnets being represented by 7o dotted circles. Fig. 9 is a bottom 'plan view of the apparatus. Fig. lb is a diagrammatic view of my signaling apparatus applied to a telephone system known as the common-battery system, patented as aforesaid, the parts 73 being represented in their normal position. Fig. 2b is a similar View illustrating the telephone-receiver of the calling subscriber A removed from its hook. Fig. 3b is a View the same as thelast, except that the central-ottico 8o operator has plugged in with her plugX on the calling subscriber A, and some of the parts of my signaling apparatus are thereby put in a position to give the second signal. Fig.

4b is a View the same as the last, except that 85 the centrale office operator has just plugged in with her plug Y on the subscriber B wanted. Fig. 5l is a similar view as the last, except that the subscriber B wanted has removed his telephone-receiverfromits hook and is in com- 9o munication with the calling subscriber A, thereby throwing my signaling apparatus in such position as to give a third signal and indicate to the central-office operator that the subscriber'B wanted has responded. Fig. 6b 95 is a view the same as the last, except that the subscriber B after responding has hung his telephone-receiver upon its hook and so actuated my signaling apparatus as to indicate this fact to the central-office operator, giving a fourth signal. Fig. 7'b is a similar View as the last, except that the telephone-receiver ofthe calling subscriber A is upon its hook and he is through, while the telephone of the subscriber B wanted is off of its hook and he is not through, thereby actuating my signaling apparatus so as to give a fifth signal and indicate these facts to the central-office operator. Fig. Sb is a similar view as the last,ex-

-cept that the telephone-receiver of the subscriber B wanted is also upon its hook, which so actuates my signaling apparatus as to put it in normal position, thereby indicating to the central-office operator that both the calling and called subscribers telephone-receivers are in their normal positions and out of use, and that disconnection of the switch-plugs X and Y should be made.

In my signaling apparatus I preferably employ two electromagnets, one of which has an interlocking armature, which latter feature is, so far as I am aware, novel in this connection, and will indicate to the operator all the different conditions of the line-wires and their electrical connections.

In the common battery telephone system Aabove referred to two magnets are employed to actuate devices to signal the central-office operator, but such magnets are not provided with an interlocking armature, and hence are incapable of giving all the necessary signals, as will be hereinafter set forth in full. Vhile my signaling apparatus is adapted for telephone systems of the character referred to it is not limited in its application to this particular telephone system, but may be applied to other telephone systems, and indeed may be used generally for signaling purposes other than telephone systems.

On Sheet I'I have illustrated my signaling apparatus without reference to a telephone system, showing that it may be applied generally for signaling, and shall now proceed to set forth the apparatus generally, having particular reference to Sheet l of the drawings.

In all the views of the drawings the same marks of reference indicate the same parts.

25 and 26 are two electromagnets. One 26 may be arranged slightly above the other. The magnet 25 is in a circuit 27 controlled by a suitable circuit-governing means or key 28.

The magnet 26 is in a circuit 29 controlled by a circuit-governing means or key 30. The magnet 25 actuates an armature 31, to which is attached a rod 32, bearing a signaling-plate at the upper end thereof. The magnet 26 actuates an armature 3e, having a downward extension 35. The armature 34 is also provided with a rod 36 and a signaling-plate 37 at the upper end thereof, the same as the rod 32, previously referred to. These signalingplates are arranged preferably beneath a plate t0, having two perforations 4l and 42therein, adjacent to the respective signaling-plates 33 and 37. The downward extension 35 of the armature 3a is adapted to come against the armature 3l. This constitutes what I term venience of expression.

of parts is illustrated in Figs. l and l and may be said to represent one signal or position of the parts. Figs. 3 and 3 illustrate what may be called a second signal or posit-ion of parts. Here the circuit 27 has been completed by the closure of the key 28, which energizes the magnet 25, causing it to draw up its armature 31 against the armature 34: and throw the signaling-plate 33 half across the perforation or hole 4l. Themagnet 26 having been left in its normal condition, its armature will be in the path of the armature 3l and prevent the latter from being drawn fully up. A signal will therefore be given different from the previous signal, wherein the holes il and 42 are both wholly unobstructed. Take the case where the circuits 27 and 29 have both been completed by the closure of the keys 2S and 30, Figs. 5 and 5a. Both magnets 25 and 26 will be energized and the armatures thereof drawn up to their fullest extent, throwing the signalingplates 33 and 37 to their fullest extent and giving, for instance, a third signal, represented by both of the holes tl and 42 being fully obstructed by their signaling-plates. Suppose, now, that after both magnets 25 and 26 have been energized the circuit 29 of the magnet 26 is opened by allowing the key 30 to rise, as illustrated in Figs. 6 and 6, the armature 3l of the magnet 26 .will partially drop, bringing the extension 35 against the armature 3l of the magnet 25. This allows the hole 42 to be partially or half uncovered by the signalingplate 37, and hence gives a dierent or what may be termed a fourth signal, the hole Il being now fully covered or obstructed and the hole 42 half covered or obstructed. If the i circuit of the magnet 25 be opened while the circuit of the magnet 2G is closed, the plate 37 will fully cover the hole 4t2, and the hole 4l will be entirely clear or unobstructed, as indicated 'in Figs. 7 and 7, whereby still another or fifth signal will be given.

Having fully set forth my signaling apparatus in its general application, I shall now proceed to set out the said apparatus applied to a telephone system. I have shown its application in Sheets 2, 3, 4, and 5 of the drawings to a telephone system of the character referred to above. In the figures of the drawings, to be hereinafter referred to, I have illustrated the talking-circuits by heavylines. It may be proper to advert to the leading features of the common battery telephone system and briefiy describe the same, which I shall now do preliminary to setting forth the application of my electrical signaling apparatus to such a telephone system. A is the calling subscriber and B the subscriber wanted. At each subscribers there is of course a telephone,an electromagnetic bell or other calling apparatus, and a telephonehook, whereby when the parts are in their normal position and the telephone is on its hook the circuit leads from a spring-jack at the central office to the electromagnetic bell, and whereby, when the telephone is removed from its hook, the hook, which is spring-actuated, breaks the bell-circuit and automatically puts the telephone in the circuit in place thereof. This is clearly illustrated in the drawings. The spring-jacks at the central office and their plugs are of Well-known construction and need no detailed description. The calling subscribcrs circuit leads to the springarms of a spring-jack for instance, and the subscriber Wanted is in a circuit Whose Wires lead to the spring-arms of a spring-jack y. These spring-jacks and gare adapted to cooperate with switch-plugs X and Y, respectively, connected to a L'attery at the central station. The plug X is used to connect with the calling subscriber and the plug Y with the subscriber Wanted.

Proceeding from contacts upon whichV the spring-armsof the spring-jack a; rests is a circuit x, containing therein a suitable battery m2 and an electromagnet x3, adapted to actuate an annunciator-drop or other indicating device. Similarly connected with the springjack y at the central station is a circuit-'Wire y', battery y2, and an electromagnet ya, controlling an annunciator-drop or indicatingv device, the same vas the magnet 41:3. The annunciator-magnets being connected as stated, it Will be evident that when asubscribers telephone is taken olf its hook this fact will be automatically announced or indicated to the central oiiice without the operator at the central office having to do anything to bring the central -oftice annunciator into requisition. The circuit of the annunciator-battery will by this be completed by Way of Wire and' the spring-arms of the spring-jack :c over the telephone-talking circuit 'va the telephonehook, as indicated at the left-hand side ot' Fig. 2b. This will energize the magnet x3 and actuate its armature, so that thenumber of the subscriber calling Will be rendered visible toA the central-otticeoperator. (SeeFig.2b.) The central-office operator novv plugs in with her plug X on the spring-jack so as to get in communication with the calling subscriber A, as shown in Fig. 3b. This plugging in breaks the circuit of the annunciator-magnet x3, for it forces the spring-arms of the sp1ing-jack away from the contacts or terminals of the circuit w of said magnet. The magnet :1:3 therefore becomes de-energized, and the annunciator isrestored to its normal position by the act of the central-office operator plugging in. The centralbfce operator now, Withtwo lingers, pinches toward each otherl the contact-buttons, putting her telephone transmitter and receiver in circuit. l(See Fig. 3b.)

The central-ofiice operator having gotten into communication with the calling subscriber, she ascertains the number of the subscriber Wanted by asking subscriber A, and then proceeds to plug in with her plug Y on the springjack y of the subscriber Wanted, (see Fig. 4b,) removing her Iingers from the contact-buttons which place her transmitter and receiver in circuit, and thereby cutting them out of circuit, Fig. 4b. This plugging in on the circuit of the subscriber wanted causes the electromagnetic bell of such subscriber to ring, Fig. 4b, and thereby announces to said subscriber that he is Wanted. This operation in nowise disturbs the 'annunciator-drop at the central station of the subscriber Wanted, for the circuit of the said annunciator-magnet is broken by the insertion ot the plug in the spring-jack.

Connected with the plug X is a circuit 27, which leads from a battery t5 at the central oflice, which battery is of considerable power, and is preferably a storage-battery. Emanating also from the storage-battery is a circuit 29, which proceeds to the poles or terminals of the plug Y. interposed between the circuits 27 and 29 are suitable induction-coils, represented diagrammatically by 47 and 48 and arranged in the manner referredv to in the aforesaid common-battery system, which induction-coils need not therefore be described in detail, as they formno part of my invention.

Having fully set forth the essential characteristics of the common-battery system, I

shall now proceed to describe the arrangement and connection of my electrical signaling apparatus in such system. The terminals of the signaling-magnet 25 are connected with the wires 27, leading to the terminals on the plug X. The signaling-magnet 26 is in the circuit of the wires 29, leading to the terminals carried by the plug Y. Connected to the circuit- 29 is a Wire 50, leading to the armature 31 of the magnet 25, and from the ar` mature 3i of the magnet 26 leads a groundwire 51, including Within its circuit abattery 52, which is employed to ringthe bell or calling apparatus ofthe subscriber Wanted. The armatures 3l and 34 are not only adapted to interlock, as previously referred to, but are adapted to come into electrical contact, eX- cept under some circumstances, and thus con1- plete the circuit of the battery 52 to the subscribers electromagnetic bell. supposing that the central-office operator has plugged in on the calling subscriber A in order to Wait on him, the position of parts, as illustrated in Fig. 3h, will result. The circuit of the magnet 25 will Ybe completed at the telephone-hook of the callingsubscriber AI and the magnet 25 will be energized by the battery 45 and will have its armature drawn up in contact with the extension 35 of the armature 34, inasmuch as the circuit of the magnet 26 is not yet com- IIO pleted and the extension 35 of the armature 34 is Within the path of the swingof the armatureBl. This will throw the signaling-plate 33 half across the hole 4l in the plate t0 and will give to the central-office operator signal No. 2, apprising her of the fact that the circuit connections so far made are complete and in operative condition, and will also advise lier that the calling subscriber stillhas his telephone off its hook and is Waiting to communicate with her. At the same time electrical communication has been established between the armature 31 and the armature 34, so that the circuit of the 'bellringing battery 52 is ready to be put into communication with the electromagnet of the bell of the subscriber wanted. The centrai-office operator now plugs in with her plug Y upon the spring-jack y of the subscriber wanted, whose telephone is still upon its hook. (See Fig. 4b.) The circuit of the signalingbattery then passes over the wire 5l to the extension 35 ofthe armature 34, va the armature 3l to the wire 50, and thence over part of the wire 29 to one of the terminals of the plug Y to the lower arm of the spring-jack y to the telephone-hook and electromagnetic-bell apparatus of the subscriber B wanted, passing therefrom to the ground and going to the other terminal ot the bell-ringing battery 52. The subscriber B wanted is thereby summoned to answer the ringing of his bell, which continues to ring until his telephone is removed from its hook. As soon as subscriber Bs telephone is removed from its hook the circuit of the bell-magnet is broken at the telephone hook and the bell ceases to ring, Fig. 5b. The raising of the subscriber Bs telephone from its hook also causes the circuit of the battery 45 to be completed by way ofthe wire 29, the electromagnet 26, the plug Y, the spring-jacl, and subscriber Bs talking-circuit. This energizes the magnet 2G and causes it to draw up its armature 34. The signaling-plate 37 will now fully cover the hole 42 in the plate 40. At the same time the contact of the armature 31 with the arm 34 will be broken and the liow of the current from the battery 52 stopped. The circuit of the magnet 25 having been previously established and the intertering action of the armature 34 of the magnet 26 having now been removed, the armature 31 of the magnet 25 will then make its full swing and thereby cause the signaling-plate 33 to completely cover its hole 41 too, and thus will indicate to the operator at the central ofiice the fact that the subscriber wanted has responded, she now having received the third signal.

I have previously stated that two magnets had heretofore been used to control the signaling apparatus heretofore used in this connection, but that the previously-used magnets were wholly independent in their operation. It frequently happens that a centraloffice operator has connected two subscribers together and she does not know Whether B is being rung up and has not answered or whether he has answered, finished his conversation, and hung up his telephone, which would break the circuit of the magnet 26 and canse the armature of this magnet to fully drop back and wholly remove the signalingplate 37 from the hole 42. If during the meantime the operator has been engaged on other matters and happens afterward to notice the signaling apparatus, she sees that the plate 37 is Wholly removed from the hole 42, and consequently comes to the conclusion that the subscriber B wanted has not responded at all. My invention obviates this diiiculty, for the signaling apparatus herein indicates the fact whether the subscriber wanted has answered and has afterward returned his telephone to itsv hook. The condition of affairs referred to is illustrated in Fig. 4l, where subscriber B is being rung up and has not answered, (hole 41 half closed, hole 42 open,) and in Fig. 6b, where subscriber B has answered, conversed, and then hung up his telephone, (hole 41 all closed, hole 42 half closed,) thus giving two entirely different signals. The magnet 26 in the latter instance, therefore, becomes de-energized, but its armature cannot drop entirely downward because it is interfered with by the armature of the magnet 25. This partially withdraws the plate 37 from the hole 42 and displays signal No. 4, which to the operator indicates that the subscriber B has responded and has replaced his telephone upon its hook. It may be supposed that when this has happened and the armatures 3l and 34 are in contact thel circuit of the battery 52 will be completed and that the subscriber Bs bell will be rung as soon as placed upon its hook, and subscriber B therefore automatically called up again as soon as haplaces his telephone upon its hook. This would happen with interlocking armatures, as described, were no provision made to prevent the same, but I provide the downward extension 35 of the armature 34 with insulating material 1I on its side adjacent to the armature 31, so that when, as in Fig. 6b, the armature 34 comes against the end of the armature 31 the insulating material referred to will prevent the completion of the circuitof the bell-magnet. The insulating material is not, however, made to cover the lower end of the extension 35of the armature 34, so that when the armature 31 comes in contact with the downward extension 35 of the armature 34 the said circuit will be completed, Fig. 4b.

In Fig. b is represented the condition of parts when the calling subscriberA has been in communication with the subscriber B and the subscriber A has replaced his telephone upon its hook, while the subscriber B has still his telephone off its hook and Waiting to communicate further with the subscriber A, or to communicate with some other subscriber, or with the central-ofiice operator. This state of facts is also indicated to the central-office operator, for now the circuit ot the magnet 25 is broken at the telephone-hook IIO of subscriber A and said magnet 25 is de-energized, allowing the signaling-plate 33 to pass wholly away from the hole 4l, While the circuit of the magnet 26 is completed by way of the subscriber Bs telephone-hook, thereby causing the plate 37 to fully cover the hole 42 and giving to the central-office operator the fifth signal. The central-office operator can then put her telephone in communication with subscriber B and ascertain his wants.

Subscriber B,if he wishes to attract the attention of the central-ottico operator without fail, can Wiggle his telephone-hook, which will vibrate the signaling-plate 37 and at once attract the operators attention.

When both subscribers have been connected up by inserting the plugs X and Y into the subscribers lrespective spring-jacks a: and y and both of the subscribers have replaced their telephones upon the hooks, a condition o f affairs exists, as shown in Fig. Sb, in which the circuits of both magnets and 26'are broken and both the signal-plates 33 and 37 are away from and uncover their respective holes. This gives the central-ottice operator the tirst signal and indicates to her that the apparatus ofy both the calling subor callingfapparatus.

scriber and the subscriber wanted is in its normal condition and out of use, and notities her to Withdraw the plugs X andYfrom their respective spring-jacks. It will thus be seen that all the different conditions of the apparatus are made known to the operator at the central station'without fail. It will also be seen that the contacting-armatures 3land 34 provide an automatic subscriber signaling So far as I am advised I believe myself to be the first to devise an automatic subscriber calling means, whereby the operator at the central office is relieved from the necessity of performing any service in calling up a subscriber. For convenience ot' construction I have illustrated and provided the central-office signaling apparatus v with the automatic subscriber calling or signaling means; but it is evident that the two may be Wholly independent ot each other, the form illustrated being theI preferred form of the invention only.

Having fully set forth one form of my invention, what I desire to claim, and secure by Letters Patent of the United States, is-

l. The combination to form a signaling apparatus, of a plate having two perforations therein, two signaling plates arranged adj acent to the perforations, electro-magnets for operating the signaling plates, having their armatures connected directly to the respective signaling plates, and anpinterlocking extension from the armature of vone of said magnets and adapted to be placed within the path of the travel of the armature of the other magnet.

2. The combination in a telephone system, of line wires leading from a central office 4to subscribers stations, calling apparatus at subscribers stations normally to line by way of telephone hooks and their front contact stops, conductors in electrical communication with a suitable battery and with the front contact stops of the telephone hooks, electromagnetic devices at the central ofce adapted to be placed in the circuit of. said line wires and conductors, and a ringing batteryy put to line by said electro-magnetic devices.

- 3. The combination in a telephone system, ot' line wires leading from a central office to subscribers stations, calling apparatus atv subscribers stations normally to line by way of telephone hooks and their front contact stops, conductors in electrical com munication kwith al suitable battery and with the front contact stops ot' the'telephone hooks, a ringing battery, means at the central office for 'central oftice operating said means to remove the ringing battery from line.

5. The combination'in a telephone system, of line Wires leading from a central oftice to subscribers stations, calling apparatus at subscribers stations, electro-magnetic devices at the central oice adapted to beplaced in thecircuit of said line wires, a ringing battery put to line by said electro-magnetic devices, and electro-magnetic appliances, be-

tween the subscriber wanted and the central office, controlling said electro-magnetic devices t'o remove the ringing battery from line.

6. The combination in a telephone system, of line wires leading from a central ottice to subscribers stations, calling apparatus at subscribers stations normally to line by way of telephone hooks and their front contact stops, conductors in electrical communication with a suitable battery andwith the front contact stops of the telephone hooks, electrofmagnetic devices at the central roffice adapted to be placed in the circuit of said line wires'and conductors, a ringing battery put to line by` said electro-magnetic devices, and electromagnetic devices at the central office, also adapted to be placed i-nv thecircuit of said line Wires and conductors, controlling the aforementioned electro-magnetic devices.

7. The combination in a telephone system, of a central ottice having talking line wires leading therefrom to subscribers, the circuits ot' which are normally broken by telephone hooks, an electromagnetic-calling apparatus at subscribers stations, the circuit of which calling apparatus isv normally closed by way ottelephone hooks, circuit-governing means and a battery at the central office' placed by the central-ofce operator in electrical control of the circuit of the calling subscriber, and a battery and electrical connections controlled by said circuit-governing means and adapted .to be placed in electrical communication with the electromagnetic-calling apparatusof the subscriber wanted.

. 8. The combination in a telephone system, ot line wires leading therefrom to the difterent subscribers, an electro-magnetic circuitcontrolling means and battery at the central rco' oftice adapted to -be placed in communication with Ia calling subscriber and a subscriber wanted, the circuit of which electro-magnetic means is normally broken by telephone hooks, an electro-magnetic-calling apparatus at the subscribers stations, the circuit of which apparatus is normallyT closed by telephone hooks, and a battery and suitable electrical connections adapted to be placed by said circuitgoverning means in electrical communication with the calling apparatus of the subscriber y wanted.

9. The combination in a telephone system, of a central ot'ce having line wires leading therefrom to subscribers, calling apparatus at subscribers stations, electrical devices at the central ofce adapted to connect a calling subscriber with a subscriber wanted, and a subscriber-calling means at the central ofce in electrical communication with said electrical devices, said subscriber-callin g means consisting of two electro-magnets adapted to be placed by said electrical devices, one within the control of the calling subscriber, and the other within the control of the subscriber wanted, a call battery governed by said magnets, and means preventing the operation of the calling apparatus of the subscriber wanted after such subscriber has responded.

lO. The combination in a telephone system, of a cent-ral office having line wi'res leading therefrom to subscribers, calling apparatus at subscribers stations, electrical devices at the y central office adapted to connect a calling subscriber with a subscriber wanted, and a subscriber-calling means at the central office in electrical communication with said electrical devices, said subscriber-calling means consisting of two electro-magnets adapted to be placed by said electrical devices, one within the control of the calling subscriber, and the other Within the control of the subscriber 1 wanted, a call battery, the circuit of which is made and broken by the contact of the armatures of said magnets, and insulating material upon the armature of the first-mentioned magnet and upon that side thereof adjacent to the armature of the other magnet for the purpose set forth.

11. The combination in a telephone system, ot' an electrical signaling apparatus at the central oflice, controlled by the circuit of the calling subscriber and adapted to display signals to the central-office operator, and a calling battery at the central office and its circuit leading to the calling apparatus of the subscriber wanted, said battery and its circuit controlled by said electrical signaling apparatus.

12. The combination in a telephone system, of an electrical signaling apparatus at the central office, controlled by the circuit of the calling subscriber and adapted to display signals to the central-office operator, electro-magmetio-calling apparatus grounded at subscribers stations, the circuit of which is closed by way of telephone hooks, and a grounded calling battery at the central office and its circuit leading to the calling apparatus of the subscriber wanted, controlled by said electrical signaling apparatus.

13. The combination in a telephone system of the character described, oi' an electrical signaling apparatus at the central olTice adapted to be placed in thecircuit of line wires leading to subscribers, and to display signals to the central-ofce operator, said signaling apparatus consisting of two electro-magnets controlling signaling devices, one of said magnets being :in the circuit of the line wire leading to the calling subscriber, and the other in the circuit of the line wire leading to the subscriber wanted, and an interlocking appliance between said magnets, whereby the said magnets may independently or conjointly operate the said signaling devices.

14. In a telephone system of the character described, an electrical signaling apparatus y at the central office adapted to be placed in f the circuit of the line wires leading to subscribers and to display signals to the centraloffice operator, said signaling apparatus consistin g of two electro-magnets each controlling signaling devices, one of said magnets adapted to be placed by the central-ottice operator in the circuit of the line Wire leading to the calling subscriber, and the other in the circuit of the line wire leading to the subscriber wanted,

and an interlocking appliance between said magnets, in combination with grounded bell- 1 magnets at subscribers stations, the circuit of which magnets is normally closed by telephone hooks, and a grounded calling-battery at the central office, the circuit leading from which to the bell-magnet of the subscriber Wanted is controlled by the aforesaid signaling apparatus.

15. The combination in a telephone system, of a signaling apparatus at the central office,

'adapted to be placed in communication with the line wires leading to subscribers and to i display signals to the central-office operator,

said electric signal .apparatus consisting ot' two electro-magnets, one placed in the circuit of the calling subscriber and the other inthe circuit leading to the subscriber wanted, a signaling device controlled by each magnet, an interlocking appliance carried by the armature of the magnet in the circuit of the subscriber wanted, insulating material upon said interlocking appliance at that side adjacent to the armature of the other magnet, and a calling battery and circuit leading therefrom to the calling apparatus of the subscriber wanted, said battery and its circuit controlled by the said signaling apparatus.

16. A combined signaling apparatus and calling device, consisting of two magnets, each of which controls a signaling device, electrical connections for governing said magnets, a downward interlocking extension from the armature of one of said magnets adapted to IOO TIO

engage with the armature of the other magnet and a calling battery and its circuit also controlled by the armatures of said magnet. v

17. A combined signaling apparatus and calling device, consisting of two magnets, each of which controls a signaling device, electrical connections for governing said magnets, a downward interlocking extension from the armature of one of said magnets adapted to engage with'the armature of the other magnet,

insulating material upon said interlocking eX- H. D. NEALY, E. E. VERNELL. 

